Structure of cerium phosphate glasses: Molecular dynamics simulation

Jincheng Du, Leopold Kokou, Jennifer L. Rygel, Yongsheng Chen, Carlo G. Pantano, Robert Woodman, James Belcher

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Abstract

We performed molecular dynamics (MD) simulations of the structure and properties of cerium-containing phosphosilicate, aluminophosphate, and aluminophosphosilicate glasses based on recent spectroscopic data that revealed 95% of cerium ions in such glasses are Ce3+. New Ce3+- and Ce4+-O2- potentials were developed and used in the MD simulations of these cerium-containing glasses with mixed glass formers. The local environments around cerium ions and network-forming cations, the medium range structure including glass-forming network Qn distribution, clustering, and second coordination shell around cerium ions have been carefully characterized. The results showed a longer Ce-O bond length and larger coordination number for Ce3+ than Ce4+ (2.48 and 6.4 vs. 2.24Å and 5.8, respectively). Around 5% of Si4+ ions were found to be in fivefold and sixfold coordination states in cerium phosphosilicate glasses, rather than the usual fourfold in silicate glasses. At the same time, the silicon-oxygen polyhedra were highly polymerized (over 80% of Q4) due to the presence of phosphorus oxide. Aluminum ions were found to be coordinated by four-, five-, and six oxygen ions, with an average coordination number of around 4.2. In both oxidation states, cerium ions were found to be preferentially surrounded by phosphorus-oxygen tetrahedra, which form a kind of solvation shell around them. The preference of network-forming cations around cerium ions in the second coordination shell was found to decrease in the sequence phosphorus, aluminum, silicon.

Original languageEnglish (US)
Pages (from-to)2393-2401
Number of pages9
JournalJournal of the American Ceramic Society
Volume94
Issue number8
DOIs
StatePublished - Aug 1 2011

All Science Journal Classification (ASJC) codes

  • Ceramics and Composites
  • Materials Chemistry

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    Du, J., Kokou, L., Rygel, J. L., Chen, Y., Pantano, C. G., Woodman, R., & Belcher, J. (2011). Structure of cerium phosphate glasses: Molecular dynamics simulation. Journal of the American Ceramic Society, 94(8), 2393-2401. https://doi.org/10.1111/j.1551-2916.2011.04514.x